Leviticus 27:3
And thy estimation shall be of the male from twenty years old even unto sixty years old, even thy estimation shall be fifty shekels of silver, after the shekel of the sanctuary. And thy estimation shall be of the male from twenty years old even unto sixty years old, even thy estimation shall be fifty shekels of silver, after the shekel of the sanctuary.
Leviticus 27 belongs to the instructions for estimating what is vowed to God in order to redeem or release it, and within those instructions the valuation of a dedicated male from twenty years old even unto sixty years old is set at fifty shekels of silver after the shekel of the sanctuary. The shekel of the sanctuary is Israel's standard of weight, and the sanctuary in that phrase means the Lord's tabernacle, the habitation of God. A person so dedicated was not to be sacrificed or put to another use, but the money could instead be paid into the Lord's house treasury in place of giving the person. What is promised to God is sacred, so when vowed property such as land or a house is retained, the priest's valuation is paid with an added fifth to make the vow good.
When a vow concerns something that could not lawfully be offered as a sacrifice, its estimated value could be given instead. Therefore Jephthah could dedicate his daughter to the Lord rather than offer her as a burnt offering, since a household member devoted by a singular vow could have been redeemed according to the priest's valuation. Because he did not redeem her, she was devoted to the Lord's service and condemned to perpetual virginity, not offered as a burnt offering.
The same chapter shows the tithe is the Lord's, bearing His image and superscription as part of the worship that belongs to God. That worship belongs to God and not to Caesar, with the tithe as part of what is God's. Civil government therefore has no right to lay any claim upon it, to exact it, modify it, or direct it in any way.